This application claims priority from Japanese Patent Application 11-056963, filed Mar. 4, 1999 (MM/DD/YY), which is commonly assigned with the present application and is hereby incorporated by reference. The contents of the present application are not necessarily identical to the contents of the priority document.
1. Technical Field
The present invention relates generally to providing an improved system of security in data processing systems and in particular to a method for prohibiting unauthorized access to data processing systems using a non-contacting (hereafter xe2x80x9cwirelessxe2x80x9d) data carrier system. Still more particularly, the present invention relates to reducing the degradation in data processing system performance inherent in effectively denying access to an unauthorized user by means of a wireless data carrier system.
2. Description of the Related Art
The current state of the art includes an RFID (Radio Frequency Identification) technique that uses a radio frequency signal to exchange ID (Identification) data. When this RFID technique is used for a PDA (Personal Data Assistant), a notebook data processing system (PC), or other data processing system, unauthorized access to specific data processing systems can be prohibited.
Discussion of the current art logically begins with a system according to which the RFID technique is used for a data processing system, such as a PDA or a notebook PC. Such a PDA or notebook PC, for which the RFID technique is used, is called an xe2x80x9cRFID data processing system.xe2x80x9d
An RFID data processing system includes an incorporated EEPROM (Electrically Erasable and Programmable Read Only Memory) storing a variety of data, including an ID, and using a radio frequency signal when transmitting data stored in the EEPROM to an external device. Upon receiving such a radio frequency signal, the external device, in turn, uses a radio frequency signal to respond to the data received from the RFID data processing system. For this, the external device determines, for example, whether the ID contained in the received data is available in its database. When the ID is available, the external device transmits a permission response to the RFID data processing system; while when the ID is not present, the external device transmits an inhibition response to the RFID data processing system.
Assuming that a LAN (Local Area Network) is constructed in a specific area, and that use of the LAN is limited to specific users while unauthorized users are denied access, an RFID data processing system such as a PDA or a notebook PC carried by a user can be conveniently used in such an area (hereinafter referred to as an xe2x80x9cunauthorized data access protection areaxe2x80x9d). In this case, a function for the exchange of radio frequency signals with an RFID data processing system is provided at the entrance to the unauthorized data access protection area, and a function for processing the exchanged data can be provided for a data processing system that is connected to the LAN. The entrance to the unauthorized data access protection area is called a portal gate.
To enter the unauthorized data access protection area, a user must input a supervisor password (e.g., a privileged-access password, hereinafter referred to as a PAP) at his or her RFID data processing system before being permitted to pass the portal gate. Thereafter, the portal gate transmits a command for setting a tamper bit, provided in the EEPROM of the RFID data processing system, to xe2x80x9c1xe2x80x9d. The tamper bit, a specific bit used to prohibit the unauthorized reading and writing of data in the EEPROM, is normally set to xe2x80x9c0,xe2x80x9d and is set to xe2x80x9c1xe2x80x9d only when an RFID data processing system has been passed through the portal gate. When the tamper bit is set to xe2x80x9c0.1,xe2x80x9d the EEPROM prohibits reading and writing of data, so that unauthorized access to the EEPROM can be prevented.
The flowchart in FIG. 8 explains the operation performed when an RFID data processing system located in the unauthorized data access protection area toggles from the power-OFF state to the power-on state. When the RFID data processing system is powered on (step S1), the POST (Power On Self Test) program examines the state of an 194 error flag, a portal gate passing error, in the EEPROM (step S2). If the 194 error flag is set to xe2x80x9c0,xe2x80x9d program control advances to step S3, while when the flag is set to xe2x80x9c1,xe2x80x9d program control goes to step S5. When the PAP has not entered, the 194 error flag is set to 111.11 At step S3, the POST determines whether the tamper bit in the EEPROM has been set to xe2x80x9c1.xe2x80x9d When the tamper bit=xe2x80x9c0xe2x80x9d (No), program control advances to step S4. When the tamper bit=xe2x80x9c1xe2x80x9d (Yes), program control moves to step S5. At step S4, the OS boot is performed and the operating system is activated. Thereafter, the RFID data processing system can be used without any constraint. That is, the RFID data processing system can be connected to the LAN in the unauthorized data access protection area, and can legally access other data processing systems connected to the LAN. Since as is described above the OS is booted when the 194 error flag=xe2x80x9c0xe2x80x9d and the tamper bit=xe2x80x9c0,xe2x80x9d no protective response occurs and the RFID data processing system is permitted to access the LAN freely. This occurs because the presence of the 194 error flag in the xe2x80x9c0xe2x80x9d state and the tamper bit in the xe2x80x9c0xe2x80x9d state imply that the PAP was entered while the RFID data processing system was on and the RFID data processing system was then passed through the portal gate (i.e., it obtained access authority).
At step S5, the POST sets the 194 error flag in the EEPROM to xe2x80x9c1.xe2x80x9d Program control then moves to step S6, where the POST displays an xe2x80x9c194 errorxe2x80x9d message, and program control advances to step S7. At step S7, the POST displays a prompt requesting the entry of the PAP. Program control thereafter advances to step S8. At step S8, the POST determines whether the PAP has been entered. If the decision is negative, program control goes to step S9. If the decision is positive, program control advances to step S10. At step S9, the POST continues to display the xe2x80x9c194 errorxe2x80x9d (xe2x80x9cERROR 194xe2x80x9d) message, and operation of the RFID data processing system by the user is thereafter prohibited. At step S10, the POST clears the 194 error flag and the tamper bit in the EEPROM. Program control then advances to step S11, where a cold boot of the system is performed. During the cold boot, the POST is again executed from the beginning.
A conventional RFID data processing system has a problem in that, when an RFID data processing system is passed through the portal gate while it is in the power-ON state, the user can continue to use the RFID data processing system until he or she turns it off manually. As a result, while in the unauthorized data access protection area the user can connect his or her RFID data processing system to the LAN and can access files stored in other data processing systems connected to the LAN, even though he or she has not been granted this authority.
The above problem will be clarified by referring to FIG. 9, wherein is shown the state transition of an RFID data processing system. In FIG. 9, the area above the time axis 15 represents a power-ON area 16, while the area below the time axis 15 represents a power-OFF area 17. At the beginning, the RFID data processing system is in the power-ON state (state 18), and in this state is passed through the portal gate (state 19). At this time, the portal gate transmits a command to set to xe2x80x9c1xe2x80x9d the tamper bit in the EEPROM of the RFID data processing system, and upon receiving this command, the RFID data processing system sets the tamper bit in the EEPROM to xe2x80x9c1xe2x80x9d (state 20). Thereafter, however, the conventional RFID data processing system permits the user to continue to operate the RFID data processing system (state 21). Thus, while operating in the 1:0 unauthorized data access protection area, the user can connect the RFID data processing system to the LAN and, without having been granted the authority to do so, can access files stored on another data processing system connected to the LAN.
When the user manually powers off the RFID data processing system (state 22) and then powers it on again (state 23), an xe2x80x9c194 errorxe2x80x9d message is displayed, as is described above. Thereafter, either a cold boot is performed or the xe2x80x9c194 errorxe2x80x9d message is continuously displayed, depending on whether the PAP is entered. In this state, the above described unauthorized access is prohibited.
As is described above, an unauthorized RFID data processing system, which was passed through the portal gate while it was in the power-ON state, can not be detected by the conventional RFID data processing system. To resolve this problem, a method has been used calls for the installation in an OS of a polling program for determining whether the tamper bit is set to xe2x80x9c1.xe2x80x9d However, since the polling method whereby a CPU (Central Processing Unit) periodically examines the state of the tamper bit, is performed regardless of the state of the tamper bit, extra CPU processing time is required. This creates a new problem, the deterioration of the performance of the RFID data processing system, is encountered when the polling method is used. The present invention is provided to resolve these problems.
It is therefore one object of the present invention to provide an improved system of security in data processing systems.
It is another object of the current invention to provide a method for prohibiting unauthorized access to data processing systems using a wireless data carrier system.
It is yet another object of the present invention to reduce the degradation in system performance inherent in effectively denying access to an unauthorized user by means of a wireless data carrier system.
To achieve the above objects, according to the present invention a wireless data carrier, used in a method that prohibits unauthorized accesses to a wireless data carrier system, comprises a CPU, a semiconductor memory, a communication device, and a power controller.
If a wireless data carrier in the power-ON state does not have access authority when it enters or exits from an unauthorized data access protection area, a signal for setting a predetermined bit in an incorporated semiconductor memory to xe2x80x9cONxe2x80x9d is transmitted to the wireless data carrier. Additionally, an interrupt request, originating at the semiconductor memory in which the predetermined bit was set ON, is issued to the power controller. Upon receiving the interrupt request, the power controller powers off.
Another method may be used according to which the CPU receives the interrupt request originating at the semiconductor memory in which the predetermined bit was set to ON. The CPU then issues a request that data be entered to acquire access authority, and if no such entry is made, disables the RFID data processing system.
As is described above, according to the method for prohibiting unauthorized access using the wireless data carrier system of the present invention, an interrupt request originating at a semiconductor memory in which a predetermined bit is set is used to prohibit unauthorized access. Therefore, unlike the prior art, wherein polling is performed to determine whether a predetermined bit has been set, extra CPU processing time is not required. And as a result, unauthorized access can be prohibited without any deterioration in performance being incurred.